The December 2023 Research Roundup. 360. looks at: Tissue integration and chondroprotective potential of acetabular labral augmentation with autograft tendon: study of a porcine model; The Irish National Orthopaedic Register under cyberattack: what happened, and what were the consequences?; An overview of machine learning in orthopaedic surgery: an educational paper; Beware of the fungus…; New evidence for COVID-19 in patients undergoing joint replacement surgery

The aim of the this study was to determine the effect of the knee flexion angle (KFA) during tibial anterior cruciate ligament (ACL) graft fixation on patient reported outcomes, graft stability, extension loss and re-operation following anatomic single-bundle ACL reconstruction. All 169 included patients (mean age 28.5 years, 65% male) were treated with anatomic single bundle ACL reconstruction using patellar tendon autograft and randomized to tibial fixation of the ACL graft at either 0o (n=85) or 30o (n=84). The primary outcome was the Knee Injury and Osteoarthritis Outcome Score (KOOS) two years following surgery. Secondary outcomes were the Marx Activity Scale (MAS), the rate of re-operation, and physical exam findings at one year including KT-1000 and side to side differences in knee extension. The follow-up rate was 82% (n=139) for the primary outcome. Graft failure rate at two years was 1% (n=2, 1 per group). ACL tibial graft fixation at 0o or 30o did not have a significant effect on KOOS scores at two years following ACLR. Patients whose graft was fixed at a knee flexion angle of 0o had greater scores on the Marx Activity Scale (mean 9.6 [95%CI 8.5-10.6] versus 8.0 [95%CI 6.9-9.1, p=0.04) and a greater proportion of patients who achieved the minimal clinical important difference (MCID) for the KOOS pain subscale (94% vs 81%, p=0.04). There was no significant difference in knee extension loss, KT-1000 measurements or re-operation between the two groups. In the setting of anatomic single-bundle ACLR using patellar tendon autograft and anteromedial portal femoral drilling, there was no difference in KOOS scores among patients fixed at 0o and 30o. Patient fixed in full extension did demonstrate higher activity scores at 2 years following surgery and a greater likelihood of achieving the MCID for KOOS pain

Background: There is limited evidence on long-term outcome following ACL reconstruction. Concern has been raised that degenerative joint disease is common in the long-term and this may be associated with use of patellar tendon autograft. Methods: 162 patients underwent single-surgeon arthroscopic ACL reconstruction (1991–1993) were identified from our prospective database. Patient-centred outcome was by Lysholm and Subjective IKDC score, objective outcome measures were clinical examination, arthrometry and X-rays. Results: 13 year outcome (10–15 years) is known in 115/161 patients (71%). The median subjective scores were 94% (Lysholm) and 90% (IKDC). Ipsilateral graft rupture rate was 4%, with contralateral ACL injury in 8%. Mean manual maximum KT 1000 was 9mm in the grafted knee and 8mm in the contralateral knee. Clinical laxity scores of grade 0 or 1 were found in over 93% patients. Radiographically 66% were normal or near normal (Grade A or B). When compared to the contra-lateral uninjured knee we found no significant difference in the proportion of normal/near normal x-rays (grade A/B) versus abnormal/severe (grade C/D) for the medial, lateral nor patellofemoral compartments. There was no significant difference in the radiological IKDC grades in the medial compartment when compared to the contra-lateral uninjured knee, but there was a difference in the lateral and patellofemoral joints. Conclusions: At 13 years patellar tendon ACLR provides excellent patient satisfaction, with clinically objective knee stability and low risk of re-rupture. Radiographically degenerative change was seen in 34%. There was no significant side to side difference to the uninjured contralateral medial knee joint, but there was a small but significant difference in the lateral and patellofemoral joints. The lateral joint differences may reflect underlying bone bruising at the time of injury. We do not believe that the patellar tendon autograft is the cause of arthrosis after BTB ACLR

In 20 skeletally mature female merino sheep, divided into four groups, we performed total medial meniscectomy, removal of the middle third of the patellar tendon, and tenotomy of the calcaneal tendon of the right hind leg. Group I (control) had no additional procedures. In the other three groups the medial meniscus was replaced by the middle third of the patellar tendon from the ipsilateral knee. The animals were killed at three (group II), six (group III), or 12 months (group IV) and the tendon-meniscus examined macroscopically, by light and scanning electron microscopy, and biomechanically. Remodelling of the tissue had taken place by 12 months but the failure stress and tensile modulus for the tendon-meniscus were lower than for the normal meniscus. Our evidence suggests that, in sheep, replacement of a meniscus by a tendon autograft may decrease the severity of the degenerative changes that occur after meniscectomy

Introduction: Some authors have suggested that the results of ACL reconstruction in females using hamstring tendon (HS) autograft are inferior to those using patellar tendon (PT) autograft. The purpose of this study was to compare our results of ACL reconstruction in females using both graft types. Material and methods: 80 females who had undergone primary ACL reconstruction using either HS (n=48) or PT (n=32) were evaluated at mean 3.7 year follow-up (2.4 – 5.7). The same surgeon carried out all the reconstructions, using Endobutton femoral fixation and interference screw tibial fixation, and the same rapid rehabilitation protocol was followed by all patients. Independent assessment included IKDC 2000, SF-36, and Cincinnati Sports Activity Score (CSAS) and measurements of anterior knee pain (AKP), kneeling pain and anterior knee laxity (KT-1000). Results: One patient in the PT group sustained a traumatic graft rupture. For the remaining patients there were no significant differences between the two graft types in terms of objective IKDC 2000 or KT-1000. In terms of subjective IKDC the HS group scored significantly higher (PT: 85 pts., HS: 90pts, p< 0.05), as well as for the CSAS (PT:72.8 vs. HS: 82.1, p< 0.01) and for the SF-36 on the Physical Functioning (PT:90 vs. HS:95, p< 0.01) and General Health subscales (PT:79 vs. HS 86, p< 0.05). Although there was no significant difference in AKP between the two groups, there was a significantly greater mean kneeling pain in the PT group (PT:4.1 vs. HS: 2.5, p=0.001). Conclusions: Both PT and HS primary ACL reconstructions appear to provide comparable good objective results in females, but ACL reconstruction with HS showed significantly better subjective results. This finding seems to be related to less donor site problems compared with PT. Our results indicate that a quadruple hamstring autograft is an adequate alternative to a patellar tendon autograft for ACL reconstruction in female patients

The bone-patellar tendon-bone (BTB) autograft has a lower rate of graft failure but a higher rate of contralateral anterior cruciate ligament (ACL) injury after primary ACL reconstruction. Subsequent contralateral injury may be a marker of success of the BTB graft, but it is unclear whether the type of graft influences the rate of return to sport. This study aimed to compare the rates of return to weekly sport and return to preinjury activity levels between the BTB and hamstring tendon autografts following primary ACL reconstruction.

Prospective data on primary ACL reconstructions recorded in the New Zealand ACL Registry between April 2014-November 2019 were analyzed. The primary outcome was return to weekly sport, defined as a Marx activity score of 8, at 2-year follow-up. The secondary outcome was return to preinjury activity level, defined as a post-operative Marx activity score that was equal or greater to the patient's preinjury Marx score. Return to sport was compared between the BTB and hamstring tendon autografts via multivariate binary logistic regression with adjustment for patient demographics.

4259 patients were analyzed, of which 50.3% were playing weekly sport (n = 2144) and 28.4% had returned to their preinjury activity level (n = 1211) at 2-year follow-up. A higher rate of return to weekly sport was observed with the BTB autograft compared to the hamstring tendon autograft (58.7% versus 47.9%, adjusted odds ratio = 1.23, p = 0.009). Furthermore, the BTB autograft had a higher rate of return to preinjury activity levels (31.5% versus 27.5%, adjusted odds ratio = 1.21, p = 0.025).

The BTB autograft is associated with a higher return to sport and may explain the higher rate of contralateral ACL injury following primary ACL reconstruction.

Introduction and Aims: This longitudinal prospective study reports the 10-year results of anterior cruciate ligament (ACL) reconstruction in 90 patients with isolated ACL rupture. Method: Three hundred and thirty-three patients undergoing endoscopic ACL reconstruction over a 15-month period using patellar tendon autograft and interference screw fixation were evaluated prospectively. Those patients with an associated ligament injury, chondral damage, previous meniscectomy, excision > 1/3 of one meniscus, an abnormal radiograph or contra-lateral knee, or a compensable injury were excluded. This left 90 patients in the study group. Evaluation was conducted annually for five years, then at seven and 10 years after surgery and included the IKDC Standard Evaluation, Lysholm knee score, kneeling pain, KT1000 testing and weight-bearing radiographs at two, five, seven and 10 years. Results: Repeat ACL injury occurred in a total of 23 patients (26%). There were six cases of graft rupture (7%) and 18 cases of contralateral ACL injury (20%). One patient suffered both a contralateral and graft ACL rupture. Eight patients (9%) underwent surgery for meniscal or chondral symptoms during the 10-year period. Of the 84 patients with intact grafts at 10 years, 75 (89%) were reviewed. On radiological examination at 10 years, 47% displayed mild to moderate evidence of osteoarthritis. The median Lysholm knee score was 95. Ninety-six percent felt their knee was normal or nearly normal. Forty-seven percent were still participating in moderate to strenuous activity after 10 years. Eighty-seven percent reported that their knee did not affect their activity level. Ninety-seven percent had grade 0–1 on Lachman and pivot shift testing. On instrumented testing 81% had < 3mm of anterior tibial displacement. Twenty-five percent displayed loss of extension range when compared to the contralateral limb, however this was < 5 degrees in 20% of patients. Pain on kneeling was present in 56%. On overall IKDC assessment, 77% were normal or nearly normal. Conclusion: Endoscopic ACL reconstruction using the PT autograft and interference screw fixation achieves and maintains excellent subjective results and objective stability. This combined with the low incidence of patients requiring subsequent meniscal or chondral surgery enforces the meniscoprotective function of ACL reconstruction. However, early signs of osteoarthritis are developing at 10 years, as displayed by radiological examination and early loss of extension

The bone-patellar tendon-bone (BTB) autograft is associated with difficulty kneeling following anterior cruciate ligament (ACL) reconstruction, however it is unclear whether it results in a more painful or symptomatic knee when compared to the hamstring tendon autograft. This study aimed to identify the rate of significant knee pain and difficulty kneeling following primary ACL reconstruction and clarify whether graft type influences the risk of these complications.

Primary ACL reconstructions prospectively recorded in the New Zealand ACL Registry between April 2014 and November 2019 were analyzed. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was analyzed to identify patients who reported significant knee pain, defined as a KOOS Pain subscale score of ≤72 points, and kneeling difficulty, defined as a patient who reported “severe” or “extreme” difficulty when they kneel. The rate of knee pain and kneeling difficulty was compared between graft types via univariate Chi-square test and multivariate binary logistic regression with adjustment for patient demographics.

4492 primary ACL reconstructions were analyzed. At 2-year follow-up, 9.3% of patients reported significant knee pain (420/4492) and 12.0% reported difficulty with kneeling (537/4492). Patients with a BTB autograft reported a higher rate of kneeling difficulty compared to patients with a hamstring tendon autograft (21.3% versus 9.4%, adjusted odds ratio = 3.12, p<0.001). There was no difference between graft types in the rate of significant knee pain (9.9% versus 9.2%, p = 0.49) or when comparing absolute values of the KOOS Pain (mean score for BTB = 88.7 versus 89.0, p = 0.37) and KOOS Symptoms subscales (mean score for BTB = 82.5 versus 82.1, p = 0.49).

The BTB autograft is a risk factor for post-operative kneeling difficulty, but it does not result in a more painful or symptomatic knee when compared to the hamstring tendon autograft.

A total of 90 patients with an isolated rupture of the anterior cruciate ligament (ACL) had a reconstruction using the ipsilateral patellar tendon secured with round-headed cannulated interference screws. Annual review for five years showed three failures of the graft (two traumatic and one atraumatic); none occurred after two years. Ten patients sustained a rupture of the contralateral ACL. At five years, 69% of those with surviving grafts continued to participate in moderate to strenuous activity. Using the International Knee Documentation Committee assessment, 90% reported their knee as being normal or nearly normal and had a median Lysholm knee score of 96 (64 to 100). Most patients (98%) had a pivot shift of grade 0 with the remaining 2% being grade 1; 90% of the group had a Lachman test of grade 0. The incidence of subsequent meniscectomy was similar in the reconstructed joint to that in the contralateral knee. Radiological examination was normal in 63 of 65 patients. Our study supports the view that reconstruction of the ACL is a reliable technique allowing full rehabilitation of the previously injured knee. In the presence of normal menisci there is a low incidence of osteoarthritic change despite continued participation in sporting activity.

Purpose: This study sought to examine return to sports in athletes younger than 25 following ACL reconstruction with either patellar tendon (PT) or hamstring (HS) autografts using a matched-pairs case-control experimental design.

Method: Twenty-three matched pairs were obtained based on gender (56.5% Female), age (18.3±2.5yrs PT vs.17.6±2.6 HS), and length of follow-up (4.7±2.1yrs PT vs. 4.2±1.6 HS). All patients reported participating in very strenuous (soccer, basketball etc.) or strenuous (skiing, tennis etc.) sporting activity 4–7 times/ week prior to their knee injury. Outcomes other than return to play included the IKDC, SAS, ADLS, SF-36, knee range of motion, laxity, and hop/jump testing.

Results: Most patients in both groups were able to participate in very strenuous or strenuous sporting activity at follow-up [18 (78.3%) PT vs. 19 (82.6%) HS]. However, only 13 (56.5%) of the patellar tendon subjects and 10 (43.5%) of the hamstrings patients were able to return to pre-injury activity levels in terms of frequency and type of sport (p=.63). Hamstrings patients showed higher ADLS (p< .01) and SAS (p< .01) scores and better restoration of extension (p< 0.05).

Conclusion: While autograft and allograft patellar tendon ACL reconstruction exhibit similar clinical outcomes in high-demand individuals, autogenous hamstring grafts may lead to better subjective outcomes in young patients who participate in very strenuous levels of activity. Both graft options only allowed approximately half of the injured athletes to return to their previous level of sporting activity.

Aim: To confirm previous studies and reports of tunnel widening following anterior cruciate ligament (ACL) reconstruction. To report the medium term behaviour and the effect of tunnel widening on the clinical results.

Methods: A retrospective analysis of the ACL database comparing BPTB autograft versus HT autograft and interference screw fixation was carried out. All procedures were performed by the same surgeon using an identical endoscopic, single-incision, surgical technique and a single method of fixation (7 x 25mm Titanium RCI screws). Patients who had a radiographic series at two and five years were included in the study. All patients had an isolated ACL injury.

Patients underwent a continuous follow up evaluation including clinical examination IKDC, Lysholm knee score and KT-1000 man max testing. Tibial tunnel widening was calculated from lateral radiographs digitalised and corrected for magnification. The tunnel shape was classified according to Peyrache.

Results: The median HT tunnel area increased significantly for the first two years (p = 0.00) and was unchanged from two to five years. The median PT tunnel area decreased significantly during the first two years (p = 0.03), and decreased again from two to five years (p = 0.02). A significant difference in tunnel shape existed between HT and PT groups (p = 0.00).

Conclusion: Tibial tunnel widening was confirmed in 79% of HT and 24% of PT ACL reconstructions utilising a single Titanium RCI screw fixation in each. Graft choice was shown to influence tibial tunnel shape; 21% of HT developed a cavity shape and 29% of PT exhibited tunnel disappearance. All patients with a decrease in tunnel area had a negative pivot shift. This was significantly different from the tunnel-widening group.

Reconstruction of the anterior cruciate ligament (ACL) allows to restore stability of the knee, in order to facilitate the return to activity (RTA). Although it is understood that the tendon autograft undergoes a ligamentous transformation postoperatively, knowledge about longitudinal microstructural differences in tissue integrity between types of tendon autografts (ie, hamstring vs. patella) remains limited. Diffusion tensor imaging (DTI) has emerged as an objective biomarker to characterize the ligamentization process of the tendon autograft following surgical reconstruction. One major limitation to its use is the need for a pre-injury baseline MRI to compare recovery of the graft, and inform RTA. Here, we explore the relationship for DTI biomarkers (fractional anisotropy, FA) between knees bilaterally, in healthy participants, with the hypothesis that agreement within a patient's knees may support the use of the contralateral knee as a reference to monitor recovery of the tendon autograft, and inform RTA. Fifteen participants with no previous history of knee injuries were enrolled in this study (age, 26.7 +/− 4.4 years; M/F, 7/8). All images were acquired on a 3T Prisma Siemens scanner using a secured flexible 18-channel coil wrapped around the knee. Both knees were scanned. A 3D anatomical Double Echo Steady State (DESS) sequence was acquired on which regions of interest (ROI) were placed consistent with the footprints of the ACL (femur, posteromedial corner on medial aspect of lateral condyle; tibia, anteromedial to intercondylar eminence). Diffusion images were acquired using fat saturation based on optimized parameters in-house. All diffusion images were pre-processed using the FMRIB FSL toolbox. The footprint ROIs of the ACL were then used to reconstruct the ligament in each patient with fiber-based probabilistic tractography (FBPT), providing a semi-automated approach for segmentation. Average FA was computed for each subject, in both knees, and then correlated against one another using a Pearson correlation to assess the degree of similarity between the ACLs. A total of 30 datasets were collected for this study (1/knee/participant; N=15). The group averaged FA (+/− standard deviation) for the FBPT segmented ACLs were found to equal 0.1683 +/− 0.0235 (dominant leg) and 0.1666 +/− 0.0225 (non-dominant leg). When comparing both knees within subjects, reliable agreement was found for the FBPT-derived ACL with a linear correlation coefficient (rho) equal to 0.87 (P < 0 .001). We sought to assess the degree of concordance in FA between the knees of healthy participants with hopes to provide a method for using the contralateral “healthy” knee in the comparison of autograft-dependent longitudinal changes in microstructural integrity, following ACL reconstruction. Our results suggest that good agreement in anisotropy can be achieved between the non-dominant and dominant knees using DTI and the FBPT segmentation method. Contralateral anisotropy of the ACL, assuming no previous injuries, may be used as a quantitative reference biomarker for monitoring the recovery of the tendon autograft following surgical reconstruction, and gather further insight as to potential differences between chosen autografts. Clinically, this may also serve as an index to supplement decision-making with respect to RTA, and reduce rates of re-injuries

Introduction. Patellofemoral instability is one of the most common presentations to a children's orthopaedic clinic. Recurrent patellar dislocations and instability episodes are painful, disabling and increase the risk of irreversible chondral damage. The medial patellofemoral ligament is the primary static stabiliser to prevent lateral dislocation of the patella and is almost always torn or attenuated in these cases. Reconstruction of this ligament is commonly performed using autologous hamstring tendon however there has been some interest recently in use of quadriceps tendon as a graft. Children with patellar instability also present unique challenges due to the small size of the patella and the presence of open growth plates which may require adaptations to the common techniques. Methods. Patients undergoing medial patellofemoral ligament reconstruction using quadriceps tendon autograft were identified using electronic theatre records. Prospectively collected clinical records and imaging findings were reviewed and underlying pathology, additional procedures at time of MPFL reconstruction, current function and need for further revision surgery determined. Results. Between January 2019 and August 2023, 50 MPFL reconstructions were performed in 37 children using partial thickness quadriceps autograft. Patient age at time of surgery ranged from 5 to 17 years (median age 13 years). The technique was utilised for a variety of indications including recurrent traumatic and habitual patellofemoral instability, fixed dislocations, and revision MPFL reconstruction. Conclusion. Partial thickness quadriceps tendon autograft can be used safely to primarily reconstruct the medial patellofemoral ligament in paediatric population, including those children with open growth plates. It also has utility in revision cases following previous failed hamstring MPFL reconstruction. We have noted that the younger the child, the more distal to the physis lies the femoral point of isometricity, rendering this a safe and reproducible treatment in this age group. Use of this technique has increased in our unit as we have observed that patients seem to be satisfied with their clinical and functional outcomes with a low incidence of short- and medium-term complications

Abstract. Purpose. This study aims to compare the clinical and functional outcomes and donor site morbidity of anterior cruciate ligament reconstruction with hamstring tendon autograft and peroneus longus tendon autograft in patients with complete anterior cruciate ligament rupture. Methods. Patients who underwent ACL reconstruction from February 2018 to July 2019 were randomly allocated into two groups (hamstring and peroneus longus). Functional scores (IKDC and Lysholm scores) and pain intensity by visual analogue score were recorded preoperatively, 3, 6months, 1, and 2 years postoperatively. Donor site morbidities were assessed with thigh circumference measurements in hamstring group and ankle scoring with the American foot and ankle score in peroneus longus group. Results. Sixty patients (hamstring n = 30, peroneus n = 30) met the inclusion criteria. The functional scores (IKDC and Lysholm) did not show statistical difference among the two groups at two years follow-up (P- value>0.05). The means values for visual analogue score after two years in the hamstring and Peroneus longus group was 1±0.74 and 1.03± 1.06, respectively. In peroneus longus group, the mean foot and ankle score was 98.63±3.88 (range= 85–100). A significant difference was found in the hamstring group between operated and non-operated thigh circumferences with p- value <0.001. Conclusions. Peroneus longus tendon autograft is an easily accessible tendon for ACL reconstruction and gives comparable functional outcomes as hamstring tendon with no additional donor site morbidity in our study

Recurrent patellar instability is a common problem and there are multiple demographic and pathoanatomic risk factors that predispose patients to dislocating their patella. The most common of these is trochlear dysplasia. In cases of severe trochlear dysplasia associated with patellar instability, a sulcus deepening trochleoplasty combined with a medial patellofemoral ligament reconstruction (MPFLR) may be indicated. Unaddressed trochlear pathology has been associated with failure and poor post-operative outcomes after stabilization. The purpose of this study is to report the clinical outcome of patients having undergone a trochleoplasty and MPFLR for recurrent lateral patellofemoral instability in the setting of high-grade trochlear dysplasia at a mean of 2 years follow-up. A prospectively collected database was used to identify 46 patients (14 bilateral) who underwent a combined primary MPFLR and trochleoplasty for recurrent patellar instability with high-grade trochlear dysplasia between August 2013 and July 2021. A single surgeon performed a thin flap trochleoplasty using a lateral para-patellar approach with lateral retinaculum lengthening in all 60 cases. A tibial tubercle osteotomy (TTO) was performed concomitantly in seven knees (11.7%) and the MPFLR was performed with a gracilis tendon autograft in 22%, an allograft tendon in 27% and a quadriceps tendon autograft in 57% of cases. Patients were assessed post-operatively at three weeks and three, six, 12 and 24 months. The primary outcome was the Banff Patellar Instability Instrument 2.0 (BPII 2.0) and secondary outcomes were incidence of recurrent instability, complications and reoperations. The mean age was 22.2 years (range, 13 to 45), 76.7% of patients were female, the mean BMI was 25.03 and the prevalence of a positive Beighton score (>4/9) was 40%. The mean follow-up was 24.3 (range, 6 to 67.7) months and only one patient was lost to follow-up before one year post-operatively. The BPII 2.0 improved significantly from a mean of 27.3 pre-operatively to 61.1 at six months (p < 0 .01) and further slight improvement to a mean of 62.1 at 12 months and 65.6 at 24 months post-operatively. Only one patient (1.6%) experienced a single event of subluxation without frank dislocation at nine months. There were three reoperations (5%): one for removal of the TTO screws and prominent chondral nail, one for second-look arthroscopy for persistent J-sign and one for mechanical symptoms associated with overgrowth of a lateral condyle cartilage repair with a bioscaffold. There were no other complications. In this patient cohort, combined MPFLR and trochleoplasty for recurrent patellar instability with severe trochlear dysplasia led to significant improvement of patient reported outcome scores and no recurrence of patellar dislocation at a mean of 2 years. Furthermore, in this series the procedure demonstrated a low rate (5%) of complications and reoperations

Introduction and Objective. Anterior cruciate ligament reconstruction (ACLR) with tendon autografts is the “gold standard” technique for surgical treatment of ACL injuries. Common tendon graft choices include patellar tendon (PT), semitendinosus/gracilis “hamstring” tendon (HT), or quadriceps tendon (QT). Healing of the graft after ACLR may be affected by graft type since the tissue is subjected to mechanical stresses during post-operative rehabilitation that play important roles in graft integration, remodeling and maturation. Abnormal mechanical loading can result in high inflammatory and degradative processes and altered extracellular matrix (ECM) synthesis and remodeling, potentially modifying tissue structure, composition, and function. Because of the importance of load and ligamentization for tendon autografts, this study was designed to compare the differential inflammatory and degradative metabolic responses to loading by three tendon types commonly used for autograft ACL reconstruction. Materials and Methods. With IRB approval (IRB # 2009879) and informed patient consent, portions of 9 QT, 7 PT and 6 HT were recovered at the time of standard of care ACLR surgeries. Tissues were minced and digested in 0.2 mg/ml collagenase solution for two hours and were then cultured in 10% FBS at 5% CO. 2. , 37°C, and 95% humidity. Once confluent, cells were plated in Collagen Type I-coated BioFlex® plates (1 × 10. 5. cells/well) and cultured for 2 days prior to the application of strain. Then, media was changed to supplemented DMEM with 2% FBS for the application of strain. Fibroblasts were subjected to continuous mechanical stimulation (2-s strain and 10-s relaxation at a 0.5 Hz frequency) at three different elongation strains (mechanical stress deprivation-0%, physiologic strain-4%, and supraphysiological strain-10%). 9. for 6 days using the Flexcell FX-4000T strain system. Media was tested for inflammatory biomarkers (PGE2, IL-8, Gro-α, and MCP-1) and degradation biomarkers (GAG content, MMP-1, MMP-2, MMP-3, TIMP-1, and TIMP-2). Significant (p<0.05) difference between graft sources were assessed with Kruskal-Wallis test and post-hoc analysis. Results are reported as median± interquartile range (IQR). Results. Differences in Inflammation-Related Biomarker Production (Figure 1): The production of PGE2 was significantly lower by HT fibroblasts compared to both QT and PT fibroblasts at all timepoints and strain levels. The production of Gro-α was significantly lower by HT fibroblasts compared to QT at all time points and strain levels, and significantly lower than PT on day 3 at 0% strain, and all strain levels on day 6. The production of IL-8 by PT fibroblasts was significantly lower than QT and HT fibroblast on day 3 at 10% strain. Differences in Degradation-Related Biomarker Production (Figure 2): The production of GAG by HT fibroblasts was significantly higher compared to both QT and PT fibroblasts on day 6 at 0% strain. The production of MMP-1 by the QT fibroblasts was significantly higher compared to HT fibroblasts on day 3 of culture at all strain levels, and in the 0% and 10% strain levels on day 6 of culture. The production of MMP-1 by the QT fibroblasts was significantly higher compared to PT fibroblasts at in the 0% and 4% strain groups on day 3 of culture. The production of TIMP-1 by the HT fibroblasts was significantly lower compared to PT fibroblasts on day 3 of culture. Conclusions. The results of this study identify potentially clinically relevant difference in the metabolic responses of tendon graft fibroblasts to strain, suggesting a lower inflammatory response by hamstring tendon fibroblasts and higher degradative response by quadriceps tendon fibroblasts. These responses may influence ACL autograft healing as well as inflammatory mediators of pain in the knee after reconstruction, which may have implications regarding graft choice and design of postoperative rehabilitation protocols for optimizing outcomes for patients undergoing ACL reconstruction. For any figures or tables, please contact the authors directly

Patellofemoral instability (PFI) is a common cause of knee pain and disability in the paediatric population. Patella alta, lateralised tibial tubercle, medial patellofemoral ligament (MPFL) deficiency, genu valgum and trochlear dysplasia are well known risk factors. A prospective database was created including patients referred through our physiotherapy pathway following first-time patella dislocation. Patella alta and lateralisation of the tibial tuberosity was treated with a Fulkerson-type tibial tubercle osteotomy(TTO). Medial patellofemoral ligament was reconstructed using quads tendon autograft pull-down technique. A modified Sheffield protocol was used postoperatively allowing weightbearing in a hinged knee brace. Forty patients were identified with 8 patients having bilateral presentations. Male to female ratio was 12:28 with an age range of 4–17 years. Eight patients had congenital PFI, five patients acquired PFI through traumatic patella dislocation and twenty-seven patients developed PFI from recurrent dislocations. Structural abnormalities were found in 38(95%) of patients. Patella alta (Caton-Deschamps index >1.2) was identified in 19(47%) patients, genu valgum in 12(30%) patients, increased tibial tubercle-trochlear groove distance(TT-TG>20mm) was present in 9(22.5%) patients and persistent femoral anteversion(> 20 deg) in 7(17%) patients. Eight patients were treated with TTO and MPFL reconstruction, three patients with MPFL reconstruction alone and five patients had guided growth for genu valgum correction. Ten patients are awaiting surgery. No postoperative patients had recurrence of PFI at their latest follow up. PFI is a common problem in the adolescent paediatric population with identifiable structural abnormalities. Correcting structural pathology with surgery leads to predictable and safe outcomes

Barriers to successful return to previous level of activity following Anterior Cruciate Ligament Recon-struction (ACLR) are multifactorial and recent research suggests that athletic performance deficits persist after completion of the rehabilitation course in a large percentage of patients. Thirty soccer athletes (26.9 ± 5.7 years old, male) with ACL injury were surgically treated with all-inside technique and semitendi-nosus tendon autograft. At 2 years from surgery, they were called back for clinical examination, self-reported psychological scores, and biomechanical outcomes (balance, strength, agility and velocity, and symmetry). Nonparametric statistical tests have been adopted for group comparisons in terms of age, concomitant presence of meniscus tear, injury on dominant leg, presence of knee laxity, presence of varus/valgus, body sides, and return to different levels of sports. Athletes with lower psychological scores showed lesser values in terms of power, resistance and neuromuscular activity as compared to the ones with good psychological scores that showed, instead, better self-reported outcomes (TLKS, CRSQ) and low fear of reinjury (TSK). In the athletes who had a functional deficit in at least one subtest, a safe return to sports could not have been recommended. Our findings confirmed that demographics, physical function, and psychological factors were related to playing the preinjury level sport at mean 2 years after surgery, sup-porting the notion that returning to sport after surgery is multifactorial. A strict qualitative and quantitative assessment of athletes’ status should be performed at different follow-ups after surgery to guarantee a safe and controlled RTP

Purpose. Elective ACLR is indicated for symptomatic instability of the knee. Despite being a common procedure, there are numerous surgical techniques, graft and fixation choices. Many have been directly compared in randomized trials and meta-analyses. The typical operation is arthroscopic-assisted, uses autograft tendon and screw fixation. Research in elective joint replacement surgery has demonstrated an inverse relationship between surgeon volume and revision and complication rates. How patient demographics, provider characteristics and graft/fixation choices influence ACLR revision rates has not been reported on a population level. We hypothesized that ACLR using tendon autograft and screw fixation performed by high volume surgeons will have the lowest rate of revision. In contrast, the risk of contralateral ACLR in the same cohort will be influenced only by patient factors. Method. All ACLR performed in Ontario from July 2003 to March 2008 on Ontario residents aged 14 to 60 were identified using physician billing, procedural and diagnostic codes from administrative databases. Data was accessed through the Institute for Clinical Evaluative Sciences. The main outcomes were revision and contralateral ACLR sought from inception until end of 2009. Patient factors (age, gender, income, co-morbidity), surgical choices (allograft or autograft tendon; screw, biodegradable or endobutton/staple fixation) and associated procedures (meniscal repair, collateral ligament surgery) were entered as covariates in a cox proportional hazards survivorship model. Mean cohort patient characteristics were chosen as reference groups. Surgical options and associated procedures were analyzed in a binary fashion (yes/no). Results. We identified 13,997 primary ACLR with a mean follow up of 3.2 years. The rate of revision ACLR was 1.8% (mean 1.9 years), and primary contralateral ACLR 2.0% (mean 2.0 years). In the cox model, younger age (14–19 yrs; HR 2.9, p<0.001), teaching hospital (HR 2.1, p<0.001) and the use of endobutton/staple fixation (HR 4.4, p=0.01) conferred a higher risk of revision. No effect of graft type or surgeon volume was found. Only younger age (14–19 yrs; HR 1.9, p=0.0005) and not any provider or surgical covariates conferred a significant risk of contralateral ACLR. Conclusion. Our results confirm that young age confers a higher risk of both revision and contralateral ACLR and these patients should be counseled accordingly pre-operatively. The use of endobutton or a staple for fixation was an independent risk for revision ACLR. This finding needs to be explored further in a direct fashion. Finally, we report that the mean time to revision ACLR was almost two years a fact that should impact future randomized controlled trial design and prompt re-evaluation of those already published which typically use only 1–2 years as the endpoint of data collection

Introduction: This biomechanical study evaluates the consequences of a mid-third BPTB-autograft excision on patellofemoral biomechanics and knee kinematics. Of particular interest was the potential role of a BPTB-autograft excision on postoperative anterior knee pain in ACL replacement surgery. Methods: Isokinetic knee extension from 120 of flexion to full extension was simulated on 9 human knee cadaver specimens (5 male, 4 female, average age at death 43 years). Joint kinematics was evaluated by ultrasound sensors (CMS 100TM, Zebris, Isny, Germany), and retro-patellar contact pressure was measured using a thin-film resistive ink pressure system (K-ScanTM 4000, Tekscan, Boston). All data were taken before and after excision of a mid-third BPTB-autograft. Results: Following excision of a mid-third patella tendon autograft we found a significant (p< 0.05) proximalization of the patella (average: 0.5 mm) and a significant decrease of patella flexion in the sagittal plane (average: 1). Patella tilt, -rotation (frontal plane), -translation (medial/lateral) and tibiarotation (external-/internal), -axis (varus-/valgus position) remained unchanged. Patellofemoral contact pressure and -area decreased significantly near knee extension (p< 0.05). Conclusions: We conclude that an excision of a mid-third patella tendon autograft results in a lengthening of the tendon with a proximalization of the patella. As the patellofemoral pressure decreases and the patella remains centralized, postoperative anterior knee pain following ACL-replacement using a BPTB autograft can not be explained by the results of our study